I call it the "high-tailer"
You put your two fingers along the horseshoe, like a two-seamer, and then slide your middle finger down, along the side below the seem. Then throw it like a fastball.
The pitch stays up and tails in to righties (if you're a righty pitcher).
I used it in a game last weekend, and it helped me throw inside to righties to brush them back. It's a useful way to come in for me, cuz deep down I'm a nice guy and there's a definite mental block I get at the last second when I try to come in. This grip plows through that mental block.
I came about this pitch while trying to make the ball sink and experimenting with different 2-seam grips ... well, it sure isn't sinking, but it does something else.